Boreholes are formed in subterranean formations for various purposes including, for example, extraction of oil and gas from the subterranean formations and extraction of geothermal heat from the subterranean formations. A borehole may be formed in a subterranean formation using a drilling assembly including an earth-boring tool, such as a rotary drill bit, coupled to a distal end of a drill string that includes a series of elongated tubular segments connected end-to-end and extending into the wellbore from the surface of the subterranean formation.
Non-limiting examples of rotary drill bits include fixed-cutter drill bits (also known in the art as “drag” bits), roller cone drill bits (also known in the art as “rock” bits), diamond-impregnated bits, and hybrid bits (which may include, for example, both fixed-cutters and roller cone cutters). The rotary drill bit can, for example, be a fixed-cutter drill bit, which typically includes a plurality of blades each carrying multiple cutting elements configured and positioned to cut, crush, shear, and/or abrade away material of the subterranean formation as the rotary drill bit is rotated under an applied axial force (known in the art as “weight-on-bit” (WOB)) to form a borehole therein. Fixed-cutter drill bits have proven very effective in achieving high rates of penetration (ROP) in drilling subterranean formations exhibiting low to medium hardness.
Cutting elements are typically laid out on a fixed-cutter drill bit in a configuration resulting in the formation of progressively smaller helical grooves in a radially outwardly extending direction as the fixed-cutter drill bit is used to form a borehole in the subterranean formation. The geometric configurations (e.g., sizes, shapes) and layout (e.g., positions, spacing) of the cutting elements within at least a shoulder region of a conventional fixed-cutter drill bit frequently results in a single cutting element performing substantially all of the work of forming the outermost diameter of the borehole. Such geometric configurations and layouts can be inefficient to produce boreholes exhibiting desirable outermost diameters, and can result in an undesirably short operational life of the fixed-cutter drill bit.
Accordingly, it would be desirable to have earth-boring tools (e.g., rotary drill bits), methods of forming earth-boring tools, and methods of forming a borehole in a subterranean formation facilitating enhanced efficiency, and prolonged operational life during drilling operations as compared to conventional earth-boring tools, methods of forming earth-boring tools, and methods of forming a borehole in a subterranean formation.